1. Field of the Invention
Embodiments of the invention relate to a method for fabricating a system in package. In particular, embodiments of the invention relate to a method for fabricating a flip chip system in package.
This application claims priority to Korean Patent Application No. 2006-2635, filed on Jan. 10, 2006, the subject matter of which is hereby incorporated by reference in its entirety.
2. Description of Related Art
Electronics manufacturers are continually seeking new designs, fabrication methods, and fabrication techniques for semiconductor devices in an effort to produce products that are smaller, lighter, faster, more efficient, more capable, and/or superior in performance, all at a relatively low cost. Fabrication techniques for reducing the size of semiconductor devices include techniques for reducing the size of components in a semiconductor device, such as the System On Chip (SOC) technique, for example, and techniques for integrating different kinds of chips into a single device, such as the System In Package (SIP) technique, for example.
A package manufactured using the SIP technique, such as a flip chip system in package, for example, may include a printed circuit board (PCB) having one surface on which semiconductor memory chips are disposed and another surface on which a semiconductor logic chip is disposed. For convenience of description, as used here, the term “system in package” refers to flip chip systems and similarly packaged systems.
FIG. 1A is a cross-sectional view of a conventional system in package strip 500. FIG. 1B is a cross-sectional view of a conventional individual system in package 200. FIG. 2 is a flow chart of a method for fabricating a conventional individual flip chip system in package.
Referring to FIGS. 1A and 2, a PCB strip 100 having an upper surface and a lower surface may be prepared, and PCB strip 100 may comprise a plurality of individual PCBs 10. A plurality of first semiconductor memory chips 1 may be stacked on an upper surface of an individual PCB 10 using an adhesive 4. Bonding wires 3 may connect ball bumps 5 of first semiconductor memory chips 1 to substrate pads 20 of individual PCB 10.
An encapsulant 60 may seal first semiconductor memory chips 1 and bonding wires 3. Conductive balls 40 may be attached to a lower surface of individual PCB 10. Alternatively, conductive balls 40 may be attached after attaching a semiconductor logic chip 2 to the individual PCB.
Semiconductor logic chip 2 may be flip chip bonded to the lower surface of individual PCB 10. Semiconductor logic chip 2 may be electrically connected to individual PCB 10 using conductive bumps 50. An underfill material 70 may be provided between semiconductor logic chip 2 and the lower surface of individual PCB 10. Fabrication of a conventional system in package strip 500 may then be complete, as shown in FIG. 1A. Conventional system in package strip 500 may then be divided into individual system in packages to form an individual system in package 200, as shown in FIG. 1B.
Next, first semiconductor memory chips 1 and semiconductor logic chip 2 disposed in individual system in package 200 may be tested and then individual system in package 200 may be sorted in accordance with the test result. If individual system in package 200 passes the test, individual system in package 200 may then be incorporated with a host device (e.g., a completed product).
Conventionally, semiconductor chips disposed in a system in package must be individually tested as any faulty chip within the system in package will dramatically impact production yields. That is, even a single faulty chip within a system in package will typically cause the entire collection (e.g., the stack) of chips in the system in package to fail.
One solution to this ensuring reliability problem has been to stack packages, rather than individual chips. However, a stack of packages is significantly thicker than a stack of chips. Hence, this proposed solution cuts against the important goal of reducing the size of electronic devices, such as mobile communication products, for example.